Comment by m132

Print was always density-independent. This didn't translate into high-density displays, however. The web, at least how I remember it, for the longest time was "best viewed in Internet Explorer at 800x600", and later 1024x768, until vector-based Flash came along :)

If my memory serves, it was Apple that popularized high pixel density in displays with the iPhone 4. They weren't the first to use such a display [1], but certainly the ones to start a chain reaction that resulted in phones adopting crazy resolutions all the way up to 4K.

It's the desktop software that mostly had problems scaling. I'm not sure about Windows Mobile. Windows Phone and UWP have adopted an Android-like model.

[1]: https://en.wikipedia.org/wiki/Retina_display#Competitors